How have moth larvae been used to control invasive prickly pear cacti?

To control invasive prickly pear cacti (Opuntia), the cactus moth (Cactoblastis cactorum) has been used as a highly effective agent of biological control.12

Native to Argentina, the moth was introduced to Australia in 1925 to combat the rapid spread of prickly pear, which had become a significant pest after being introduced without its natural predators. The larvae of the cactus moth destroy the plants by burrowing into them, feeding on the internal tissues.123

This intervention proved remarkably successful; by 1933, major infestations were under control, and approximately 24 million hectares (60 million acres) of land were reclaimed from cactus thickets for use as plowland and pasture. While biological control is a valuable tool for managing invasive species in uncultivated areas, it requires careful management to ensure that introduced organisms do not themselves become pests in their new environments.2